@Ian2: I'm not sure if I understand you correctly. Umbraco don't support model, when you have one page and two (or more) contents (each one in different language) connected to that page. So Umbraco won't detect what is your current language in browser or operating system and decide which content should be displayed.

You have to create 1 page with English content (ex. about_EN), and 2nd page with Polish content (ex. about_PL). Each page will have different Url and different content.

Now depending on with language you users want to use, they will open 1st or 2nd page.